The invention relates to an installation for treating, in particular for painting, objects, in particular vehicle bodies, having
a) at least one bath in which there is a treatment fluid, in particular paint, in which the objects are to be immersed;
b) a conveyor device by means of which the objects can be guided through the installation in a continuous or intermittent translatory movement;
c) a plurality of immersion devices which each support an object on a supporting structure connected to the conveyor device by way of a connecting structure and are able to immerse this object in the bath.
An installation of this type is described in DE 196 41 048 C2. In this, the immersion devices are constructed such that the objects to be treatedxe2x80x94in the exemplary embodiment illustrated, vehicle bodies to be paintedxe2x80x94are immersed in the baths and lifted out of these again with a superimposition of the translatory movement and a rotary movement about an axis aligned perpendicularly to the transport direction. Here, the connecting structures of these immersion devices are inherently rigid holding frames, a single axis of rotation for the rotary movement being located in the lower middle region thereof, as seen in the normal position. The purpose of this installation is to enable the objects to be treated to be completely immersed in the baths along a relatively short path of the translatory movement, so that the end walls of the baths can be steep and the baths as a whole can be short. The disadvantage is that the objects to be treated have to be placed completely xe2x80x9con their headxe2x80x9d. In the case of objects which have a considerable weight, this calls for very expensive holding frames and large forces. If the objects to be treated are vehicle bodies, their movable parts, for example doors, boots and bonnets, have to be secured against swinging open. Moreover, kinematically speaking, these known immersion devices permit only one type of immersion movement, that is the rotary movement, which is not optimal for many objects which have unfavourable geometries for this.
The object of the present invention is to further develop an installation of the type mentioned at the outset, such that, whilst using substantially equally short baths, it is not necessary to rotate the objects to be treated through 180xc2x0 and it is possible to devise the kinematics of the immersion procedure such that they may be more varied. This object is achieved according to the invention in that
d) the connecting structure has at least one steering linkage which in turn comprises:
da) two steering means which are arranged at a distance from one another and are connected in articulated manner to the conveyor device at one end and in articulated manner to the supporting structure at the other end;
db) at least one device by means of which at least one of the two steering means of the steering linkage can be rotated about the axis produced by its articulated connection to the conveyor device.
According to the invention, therefore, a steering linkage is used within the connecting structure which has each immersion device, said steering linkage enabling precise guidance of the objects to be treated, even in their orientation with respect to the horizontal. Key factors here are two steering means which are arranged at a distance from one another and connect the conveyor device to the supporting structure. If at least one of these steering means is rotated about the axis of articulation, which corresponds to its articulated connection to the conveyor device, the entire steering linkage follows with kinematics which correspond in detail to the design of this steering linkage. In each case, the point at which the rotatable steering means is connected to the supporting structure in articulated manner can be moved by a vertical difference which corresponds to double the length of this steering means.
In the simplest case, both steering means of the steering linkage are rigid one-piece parts. The steering linkage thus forms a type of parallelogram guide, in which two sides of the parallelogram are formed by the two steering means, one side by the conveyor device and one side by the supporting structure. If at least one of the two steering means is rotated, for example by a motor, the height of the parallelogram alters; the object held by the supporting structure passes through a vertical movement, which can be either an immersion or a removal movement. During this, the object itself maintains its original orientation with respect to the horizontal. The direction and speed with which the steering means is rotated can be matched to the translatory movement of the entire immersion device such that the object is immersed in, or lifted out of, the bath in virtually vertical manner.
A much more variable embodiment of the invention is the particularly preferred embodiment in which one of the two steering means of the steering linkage comprises two steering elements which are movably connected to one another, and in which, associated with both steering means, there is in each case a device by means of which the particular steering means can be rotated about the axis produced by its articulated connection to the conveyor device independently of the other steering means.
This embodiment of the invention enables a plurality of kinematics for immersing and removing the objects in and out of the baths. As a result of one of the two steering means being composed of two steering elements which are movably connected to one another, the two steering means can, to a certain extent, be rotated independently of one another. This means in particular that the vertical movement of the objects to be treated can now be linked in virtually any manner with a rotary movement about a horizontal axis. The vertical and rotary movements are completely independent of one another and are furthermore also independent of the translatory movement which the objects execute through the conveyor device. The selected kinematics can be adapted in optimum manner to the particular geometry of the objects to be treated. In the case of vehicle bodies, for example, the immersion procedure can be devised to ensure an optimum flow along the various inner and outer faces and also good ventilation of the inner cavities.
The two steering elements of the one steering means can be mutually connected in articulatedxe2x80x94although preferably linearly displaceablexe2x80x94manner. In both cases, they give the corresponding steering means the degree of freedom necessary for its independent rotation.
The connecting structure expediently has two steering linkages of the type described above, which are arranged at a mutual parallel spacing. In this case, the movement of the two steering linkages is synchronised in suitable manner.
It is particularly favourable here when the two steering linkages are arranged parallel to the transport direction of the conveyor device. In this case, all those components which belong to the conveyor technology can be located to the side of the baths, so that these latter cannot be contaminated by impurities falling or dropping down from the conveyor technology.